Bill Cheek - World Scanner Report

Publisher/Editor: H. D. Cheek, Sr. aka 'Dr. Hioortortis '

V1N5: Hay-June, 1991

THE WORLD SCANNER REPORT
A Journal of VHF-UHF Scanner Technology 4 Engineering

Mshed at; COMMtronics Enqinseringi PQ BOX 262478; San Diego. Cft 92196 Copyright (c) 1991 <ftll Rights Reserved) $4,00

THIS IS A COMBINED ISSUE ADDING CUi & SSB TO YOUR SCANNER ?

Remember, we publish ten times a year so this issue marks
the half-way point for 1 991 , and is more or less combined
with June as a single issue. You won’t get a June issue,
specifically. The same thing will happen at the end of
the year when November and December are combined.

THIS MAY BE YOUR LAST ISSUE UNLESS YOU RENEW SOON!

Check the ’’Expire Date” in the upper right corner of your
mail label. If it says ’’May 91”, then your subscription
will expire with this issue. You can renew any time to
take up where this issue leaves off. If your budget is
tight for this month, drop a line saying so, and we’ll go
ahead and send the July issue on time and trust that you
will renew before the August issue comes out. If you
don’t plan to renew, drop a note to briefly say why not
and we’ll send you the July issue anyway just to express
our appreciation of your patronage. Fair enough?

IF YOU WANT TO RENEW

Then do so right away so we can lay plans for the next
r. You can take advantage of decent discounts and
lcnewing for one full year, or even two for the maximum.
Rates are unchanged at $15/6-mos; $25/yr or $45/2-yr. We
are growing and we’re getting better. Please come along!

NOTE THE NEW TYPE STYLE IN THIS ISSUE

Actually, it’s not new; we’ve had it all along. It’s

just that this particular printer is about as slow as

molasses flowing through a straw in the winter. That’s
not the only reason it has not been used before? this
print is about 12$ larger, which means a 12$ reduction in
the amount of information. In the past, I felt you might
prefer more info at the expense of a less neat typestyle.
There have been several justifiable complaints, however,
so I’ll try this style of print on you and see how you
like it. Your feedback will be appreciated and it might

even influence the decision on whether or not we stick

with it. Is it a good tradeoff? Please tell me!

ERRORS IN VOL-2 OF THE SCANNER MODIFICATION HANDBOOK

Three technical errors have emerged in Vol-2 of the SMH
so far. Please make corrections in your copy of the book
as follows: Page 58; Step 7.B: Change ”IC-5, Pin 10” to

Pin 12”. Then turn to page 83; MOD-5, Step C:
nge ’’Pin 3 of IC-6” to ’’Pin 6 of IC-6”. Then, in the
next sentence, change "PR0-2004” to ’’PR0-2005”. That’s
all the glitches so far other than ignorant typos. Sorry
for any inconveniences this stupidity may have caused.

This has been a back burner project of mine for over a
year now, and I just haven’t gotten around to working out
the details. Recently, a reader sent me info about an
article in the May-1990, issue of POPULAR ELECTRONICS
MAGAZINE, titled ’’Add CW & SSB To Any Shortwave Receiver”
by Michael Covington. The circuit is super simple and I
hoped it might do the trick. Maybe not, because I tried
it six different ways and it failed to work. Maybe I am
overlooking something. Have any of you tried it? The
principle seems sound but I’m missing out on something.
I’ll be glad to send the info to anyone who would be
interested in brewing up this little circuit and report
the results back to me. If you want the info, send me a
SASE and one loose extra stamp. The principle of this
circuit makes it a credible candidate for SSB detection
in the PR0-2004/5/6 scanners and other scanners which
have the AM mode and 25-30 MHz coverage.

Just understand that SSB on 30 MHz and up is practically
non-existent though apparently the new Land Mobile band,
222-225 MHz has been authorized for Amplitude Compandored
Sideband (ACSB). United Parcel Service was planning to
set up a nationwide dispatch/shipment tracking system on
this band using ACSB but I hear that it has been either
delayed or shelved for the time being. Maybe in time,
we’ll see some SSB activity on VHF & UHF. For now, the
only SSB of significance is between 27-30 MHz; CB’ers,
Freebanders and Hams operate SSB in that range. There
may also be a few survivalist groups operating with SSB
between 25.5 MHz and 26.5 MHz.

A FANTASTIC SOURCE OF ELECTRONIC PARTS & SUPPLIES

Most of my modifications and electronic projects are
designed around the Radio Shack catalog because it is
such a universal reference book and it’s best that we all
play to the same ’’sheet of music”, so to speak. Alas,
Radio Shack steps to the beat of its own drummer and does
not carry many things needed by the electronic hobbyist.
liJe have to turn to outside sources for the more critical
chips, parts and supplies for our modifications. By and
large, you’re referred to ’’your local electronics supply
house” in my books and here in the ”ti)SR". Come to find
out that many readers just don’t know where else to turn
if Radio Shack can’t meet their needs. Relax now!

DIGI-KEY CQRP, a large mail-order electronic supply firm
puts Radio Shack to shame in the parts department and the
prices are hard to beat! Digi-Key claims to ship 99$ of
all orders within 24-hours, also hard to beat. Get on
their mailing list for a great catalog which is issued
every 2-months. Write or call as follows:

Digi-Key Corporation; PO Box 677; Thief River Falls, MINN
56701-0677, or call (BOO) 344-4539. Digi-Key has an
extensive inventory of small electronic parts, including
chips of all brands & kinds, transistors, resistors,
capacitors, coils, chokes, resonators, crystals, LEDs and
relays. Digi-Key also has a good stock of electronic
tools and test equipment. And they deal in nickels and
dimes as well as in bucks! Definitely hobbyist oriented!

=-=-=- FROM FIDONET 1 5 COMPUTER BULLETIN BOARDS -=-=-=

Public Message (Sent)

Message ff 9136 ^SHORT-WAVE*

To : Paul Scalzo

From : John Mccolman
Subject : Re: AR-3000 RECEIVER
Date : 91/04/08 1::3:00

I ! ve been satisfied with the sensitivity of the AR-3000,
not overwhelmed, but definitely satisfied. The extra
little features like for search (being able to lockout
individual frequencies) makes the radio unique. It is
not as fast as I’d hoped, but I like it overall.

TBBS V2.1/NM

* Origin: ANARC BBS-Assoc.of North American Radio Clubs
(913)345-1978 (280/3)

Message #8443 - SHORTWAVE

From : Dan Morisseau on (1:202/701)

To : Chris Conner on (1:202/719)

Subject : A0R AR-2500
Date : 14-Apr-91 22:23

CC> I am interested in purchasing a continuous coverage
CC> scanner and I am considering the AR-2500. Can anyone
CC> who has had some experience with this particular
CC> model please let me know how you liked/disliked it.

Chris - I owned a 2500 for about 25 days and felt obliged
to return it to ACE for the promised refund. It was
extremely plagued by images from commercial FM broadcast
throughout the VHF-Hi band and was just plain impossible
to use on VHF-Lo because of birdies. I tried a number of
’’fixes” suggested by ACE, including an FM trap from Radio
Shack and a higher output power supply. Nothing worked to
any degree of satisfaction. It WOULD work on UHF freqs IF
the attenuator was switched in. Performance on freqs
below 30 mHz was not fully explored, but from what little
I did play around, it seemed to be worse than VHF. In
short, Chris, I would not recommend this unit to anyone,
based on my experience. I have since taken the money I
put in the AR2500 (and more) and invested in an IC0M
R-7000. I am more than satisfied that I got my moneys
worth there. Suggest that you save yourself a great deal
of inconvenience and disappointment and search for
another radio. As I said above, the ICQM R-7000 is a lot
more expensive, but it is a lot more radio, too.

* Origin: The Boardwalk! * Master Series Support *

206-941-3124 (1:343/47) [EDITOR’S NOTE: This message was
edited for brevity.]

CELLULAR & OTHER MODS FOR THE REGENCY TS-2 TURBO-SCANNER

I haven’t actually done the cellular restoration mod, but
thanks to Larry Rosen who sent me a copy of the Service
Manual for the TS-2, I was able to determine a prob
best course of action. Remove the top cover and examine
the top-right-front area of the receiver behind the front
panel and locate the ’’Processor PCB Assy”. There will be
a large 40-pin IC chip, U-502, to capture your immediate
and exclusive interest. Find Pin 40 and nearby resistor,
R-512. Examine the board, front or back, between R-512
and Pin 40 and note where Pin 40 is jumpered or wired to
ground. Remove or clip that ground to restore cellular
capability. BEWARE that intercepting cellular phone
calls is a violation of the ECPA. A review of the TS-2
Manual suggests several other possibilities for mods:

(1) A standard 16-pin NFM chip is used, so refer to VI N4,
page 6 and associated articles for hints in this area.

(2) A speedup might be achieved by replacing Y-501 , a
4.19 MHz crystal with something 50-100? higher in freq.

(3) SW Interface (MOD-14); Extend Delay (MOD-29); Event
Counter (MOD-30); CTCSS (MOD-31); Carrier-On Indicator
(MOD-32); and the Auto Tape Recorder Switch (MOD-33) all
should be possible to do on this rig. (4) TAPE RECORDER
output is probable by tapping the high side of the Volume
Control via a 0.1 -uF capacitor. Use shielded mic cable
to the new jack if you install one. (5) S-metering is
probably not feasible in this unit. (6) Extra memory
channels and recovery of other freqs also not probable

-=-=-= THE SCANNER MODIFICATION HANDBOOK CORNER -=-=-=
MOD-30 Event Counter Note

A slick little mod that’s easy to do and can be most
useful not only with your scanner but perhaps in other
areas limited only by your imagination. The Counter
Module requires a ”AA” flashlight battery for operation.
If you’re like me, your first instinct was something
like, ”Aw, geez, not another battery to run down every
few days”. Change ’’days” to years. I’ve had a cheap AA
battery in my Event Counter for over six months now, and
the terminal voltage still measures over 1.5-v. Moral :
don’t bother with trying to feed external power to the
module as I first considered. Just replace the battery
every 6-12 months whether needed or not!

PRJ-3 Snatch ’N Latch DTMF Decoder Note

Vol-2 of my book discusses a super slick telephone dial
tone decoder that can be used to decode dial tones that
you hear over your scanner or dial tones from just about
any source, including direct from the phone lines and
from recordings made on tape. HB Technologies,
developer, now has available an etched circuit bo,
ready to stuff with a handful of components to complete
the Snatch *N Latch project. They even supply the more
difficult to obtain DTMF decoder chip, and perhaps other

’’THE WORLD SCANNER REPORT" (c) 1991

V1N5- Page 2

parts* The availability of the printed circuit board
makes this project a snap. Write to HB Technologies, PO
Box 2771, Spring Valley, CA 91979 for more info.

The Snatch ’N Latch DTMF Decoder board can be installed
a small project box or even inside of most scanners.
i ve built two so far, one that will fit into a pocket
for portability and the other is attached to my PR0-2Q04
TurboliJhopper scanner via a remote box and umbilical
cable. A neat and sometime useful snoop gadget!

The New Wish List; Item 4

Electronic RF Attenuators may now be available that can
be adapted to our scanners! Chris Storey of Los Angeles,
CA, called my attention to a ,t TTL Controlled Attenuator"
made by Mini-Circuits, Inc, PO Box 350166; Brooklyn, NY
11235-0003; (718) 332-4661. The 50-ohm TOAT-series

performs with 6-usec switching speed and handles power
levels up to 1 -milliwatt. Several styles and packages
are available, some that look like IC chips and others in
a metal enclosure with connectors. Contact Mini-Circuits
for more info. Suitability for scanners is not known at
this time, but you can ask them!

The New Wish List; Item 9

I haven’t done the hypothetical "High Speed Electronic
Antenna Switcher" discussed on pages 216-217 in Vol-2,
but the idea still gnaws at me. Every now and again I
w nk at the diagram on page 217, and an "error" jumped up
me that 1*11 tell you about here. Refer to the right
side of the drawing at the 8-pin connector. Notice where
I have shown jumpers from Pins 1 & 2 and 3 & 4? Well,
this would cause immediate problems if you tried to use
two bands to control one antenna as shown. Instead of
the jumpers as shown in Fig 5-1, we’ll use some isolation
diodes, so refer to the corrected method below:

Another change for the better that occurred to me to
mention is to change the 1-k resistors to 2.2k, 2.7k, or
even 3.3k to avoid loading down the front end circuit.
The 470k resistor might be reduced to 220k, but it must
remain a rather high value, certainly above 100k. Has
anyone experimented with this circuit yet?

=-=- BOOK REVIEW: THE UNIDEN COOKBOOK -=-=

3 one’s for you hams, CB’ers and Freebanders who use
any of several transceivers of Uniden origin including
the HR2510, HR2600, Realistic HTX-100 and the Lincoln

export rigs. The UNIDEN COOKBOOK is a compilation of
some 20 mods, tips, tricks and kinks on the above radios.
Among this hot stuff are power increases, variable power
controls, improvements in the noise blanker and audio
circuits, and troubleshooting charts. Easy to read and
comprehend, THE UNIDEN COOKBOOK is available from its

author as follows: > Bud Stacey KC4HGH; P0 Box 907;

Satsuma, AL 36572 < I don’t remember the price, so

send Bud a SASE and an extra loose stamp for the details.

=-=- A READER’S REVIEW OF THE ICQM 24/AT TRANSCEIVER -=-=

I am a licensed ham, so the appeal of the IC0M 24/AT
Handheld was too much to pass up. I spend lots more time
scanning than hamming, so the idea of a scanner that also
transmits (for highway emergencies or just socializing)
was a bit too much to pass up. Of course, IC0M sells the
24/AT as a ham radio that just happens to scan. The out-
of-band receive/scan features are not emphasized. The
24/AT scans 40 channels between 75 MHz and about 1 GHz.
Operation of the unit side by side with a Bearcat 200 XLT
on the VHF-Hi & UHF bands indicates that the sensitivity
of the 24/AT is notably superior. In the B60 MHz range,
I’d give the IC0M a slight edge. I won’t elaborate on
the ham related features since that’s a bit beyond the
scope of the "WSR" except to say it is an outstanding
unit with exceptional performance. I will offer some
comments to potential buyers of the 24/AT as a scanner:

The scan speed is slow compared to the conventional
Uniden/Realistic scanner. The priority channel cannot be
used while you are scanning. When you turn the unit ON,
it does not automatically resume scanning, you must
manually initiate the scan function. There are bells and
whistles, like signal strength display, auto turn on/off
timers. Generally, all can be selected or deselected.

The large number of keyboard selectable features often
requires that more than one button on the small keyboard
be pressed at once, so it is difficult to invoke these
options while driving or walking. All in all, I give the
24/AT very high marks, though it takes a little while to
adjust to its complexity and peculiarities.

By: D. L. Goodson; Orlando, FL
[EDITOR’S COMMENT: One wonders if the 24/AT can be made
to transmit out-of-band; some do, I understand....... /be]

=-=- A TIP ON EXTERNAL SPEAKERS -=-=

If you’re deaf in one ear and can’t hear out of the other
like me, then you probably find lots of fault with the
speaker that’s in your scanner. It’s cheap, funky and
ineffectual unless you’re sitting right on top of it. I
found a great all-purpose extension speaker some years
ago that’s still available today. Radio Shack’s CB
Extension Speaker, § 21-549 is a real performer for the
tone deaf like me. What makes it so good, not to mention
the compact case, nice mounting bracket and long cord, is
the actual speaker element inside the case! It’s got a

"THE WORLD SCANNER REPORT" (c) 1991

VI N5 - Page 3

huge magnet on a sturdy frame quite similar to #40-1197
replacement speaker. The bottom line is that it works
very well for the intended purpose.

Hobbyists sometimes go to unneeded extremes to fashion
external speakers for the listening post. I’ve seen
costly stereo speakers in use that didn’t sound any
better than the scanner’s stock speaker. No wonder. The
audio reproduction circuits in shortwave and scanner
receivers are designed for the VOICE band of 300 Hz to
3000 Hz and that’s all that the speaker will ever get..
It makes no sense, then, to go overboard. In fact, best
is sometimes worse in this case. Fidelity is one thing
and intelligibility can be quite another. Your home
stereo requires fidelity but your listening post demands
intelligibility! Communications receivers can produce
distortion above and below the voice band which can be
reproduced in a hi-fi speaker to muddle or diminish the
needed intelligibility. It’s best to select a speaker
precisely tailored for radio comm, and that means center
performance at about 1.5 KHz with upper and lower cutoffs
of about 3 KHz & 300 Hz, respectively. Radio Shack’s CB
Extension speaker is eminently suited for this job. And,
it’s very, very rugged; ideal for mobile, portable and
most any other commo application.

=-=- NEW CELLULAR PHONE BANDS -=-=

Right after Vol-1 of my Scanner Modification Handbook
went to press, the FCC authorized additional channels for
the CMT bands. This may or may not render obsolete the
charts & tables in Vol-1, pages 64, 66, 68 & 69, because
the new freqs are not in use in all areas yet. Cellular
phone bands are listed below for your references

FROM

TO

CLASS

NATURE OF SERVICES

824.010

834.990

Cell

Mobiles

Non-telephone Company

835.020

844. 9B0

Cell

Mobiles

Telephone Company

845.010

846.480

Cell

Mobiles

Non-telephone Company

846.510

849.000

Cell

Mobiles

Telephone Company

869.01 C

B79.990

Cell

Bases

Non-telephone Company

880.020

889.980

Cell

Bases

Telephone Company

890.010

891.480

Cell

Bases

Non-telephone Company

891.510

894.000

Cell

Bases

Telephone Company

As you may know, cellular mobiles are not usually worth
monitoring because of very short range and one-sided
conversations. Incidentally, the mobile frequencies are
always exactly 45.000 MHz below the base frequencies. So
if you hear a cell site on 891.540, the mobile will be on
846.540. NOTE: it is illegal to monitor cell mobiles and
bases, but you knew that anyway. I just mention it again
to keep from getting jailed for making you think it’s ok.

=-=- MODS, TRICKS & STUFF FOR THE PRO-34 -=-=
Handheld scanners are pretty neat, but they’re used about

90$ of the time in fixed locations, usually the listening
post. It would be neater if they came with some of the
frills, bells and whistles common to base scanners. But
then handheld scanners sometimes need bells and whistles
in portable operations, too. 0k, we will just have to
the job for ourselves. ATTENTION PRIVATE DETECTIVES ^
LAW ENFORCEMENT PERSONNEL: The first two mods below may
be eminently applicable to your needs!

Tape Recorder Output Jack

This one is easy. The ’’high" lug of the Volume Control
carries just the right level of audio signal for most any
tape recorder and it’s accessible. But where to put a
jack? Remember, we have to keep the scanner maintainable
and easy to disassemble, so we don’t want any jacks
installed in the plastic case to complicate future access
and maintenance. No sweat! First snag a pair of submini
3/32" phone jacks, RS # 274-247 and a 0.1 -uF capacitor, RS
#272-135 or 272-1069. That will be all you’ll need here.
Save the spare 3/32" jack because you’ll need it below
for the Automatic Tape Recorder Switch.

Remove the back plastic case of the PRO-34 and lay it
aside. Position the scanner so that you’re looking at
the rear, exposed circuit board with controls up and
battery compartment down. Now eyeball the area of the

upper left corner where the Volume Control is and then
downward an inch or so to T-102. That area between T-102
and the Volume Control along the edge of the PCB is qu5*“'
flat and unencumbered with parts. A perfect place
super-glue one of the 3/32" phone jacks on its side with
the plug opening pointing outward to the left side. Move
the jack around a little first to make sure the scanner’s
case can be reinstalled without touching the jack. In
other words, the jack will be recessed from the side
panel just a little and permanently affixed to the
circuit board. No problem... the jack will never be a
bother that way! When you see what I am talking about
here, put a drop of super glue on the plastic side of the
3/32" jack and press it to the PCB on the chosen spot.
Again, be sure the jack opening is recessed in a little
to permit the case to easily go on and off.

Solder one lead of the 0.1 -uF capacitor to the high lug
of the Volume control. One end lug of the Vol control is
ground and has a BLACK wire, so the other end lug with
the GREEN wire is the one where to solder the capacitor.
Solder the other lead of the capacitor to the rear lug of
the 3/32" jack that’s farthest from the ground lug.
Solder the ground lug of the 3/32" jack to a nearby PCB
ground trace. You may have to scrape some green lacquer
off the ground trace first. When done, there will be an
unconnected lug on the 3/32" jack, and that lug will be
between the ground lug and the hot lug.

Temporarily reinstall the rear case.... and mark where a
hole will have to be in order to access the jack from
outside. This is a trial & error operation mostly, and

"THE WORLD SCANNER REPORT" (c) 1991

VI N5 - Page 4

when you think you’ve got the spot, drill or melt a tiny
hole through the side of the case to align with the jack
opening. Then close the case to make sure your hole is
on center with the jack. If not, make enlargements of
that hole in the necessary direction to get it centered
r the jack. Once you f re sure it’s centered, then
drill it out to 3/8" diameter, to accommodate the plug
that will be needed! That's it; you 1 re almost done now.
Hake up a patch cord with shielded coax or mic cable to
fit between this jack and your tape recorder. You can
now record any signal that’s picked up by the PRO-34.
Furthermore, the mod is self-contained and will never
hinder future access to the innards of the scanner!

Automatic Tape Recorder Switch For the PRO-34

Tape recorder jacks on scanners are mostly worthless
unless you’re right there, johnny on the spot, to operate
the damn things all the time. A tape recorder output and
my Automatic Tape Recorder Switch (ATRS) go together like
kids and puppies, however. See Vol-1 , MOD-5 and Vol-2,
MOD-33 for two varieties of ATRS. We will use MOD-33 in
the PRO-34 by virtue of its simplicity and smaller size.
Instead of building MOD-33 on a perf board as shown in
V ol-2, we’ll have to build it component by component
right into the PRO-34. Space in there is very limited,
you see and we need to keep things condensed. But it's
not difficult as you will see.

The hardest part is the 3/32” jack required for the
ate Control function output but it's no more difficult
u<an the jack we installed just above for the Tape Rec
Output. Remove the rear case of the PRO-34 again and
scope out the left side of the exposed PCB. Find T-102
again and then just down the board from it is a thing
that looks like a quartz crystal, XF-101. Well, right
there between T-102 and XF-101 is a prime spot for the
3/32” Remote jack... almost. Try a fit and you’ll see
that it’s tight. File the sides and lower corner edges
of the 3/32" jack until the fit is perfect. It won’t

take much. Taking the same precautions described above

for the Tape Recorder Output jack, super-glue the Remote
jack to the PCB so that the jack opening points outward

to the side of the case but does not get in the way of

opening and closing the case. Now put the rear case back
on and mark a spot that centers over the opening of the
3/32” Remote jack. When you’re sure it’s centered, drill
out a 3/8" hole to accommodate a Remote patch cable.

Use the diagram on page 188 in Vol-2 of my book, but
three of tie parts will change. Instead of the relay
called for there, use RS #275-232, a 5-v reed relay; it’s
small with low current needs! R-1 and R-2 should be
changed to a single 100-k resistor, RS #271-1347. Install
the LED (D-2) to be visible as a "Carrier On Indicator"
you want; it is necessary for the circuit but it
Jn’t be visible unless you want. I installed my LED
in a hole between the Volume and Squelch Controls! Now
decide where to install the On-Off switch for the ATRS.

I installed mine between the Antenna Connector and the
Squelch Control. The RS micromini toggle switch #275-624
is suitable but don’t use anything larger.

Super-glue Q-1 , the 2N2222A switching transistor, upside
down to the top of IC-101 on the PRO-34 ’s PCB. Solder
one end of the 100-k resistor (new R-1) to Pin 13 of
IC-101 and the other end to the base of Q-1. Solder the
emitter of Q-1 to a nearby PCB ground spot. Physically
lay the reed relay (pins up) in the uncongested area
between C-205, TP-105 and C-216. It will kind of wedge
in there without harm. Assuming that the LED and on/off
switch are mechanically installed, complete the wiring of
the relay, D-2 LED, S-1 , J-1 and D-1 in accordance with
the diagram on page 188 in Vol-2, and that will do it!
Be critical of your hookup wire; use wires salvaged from
RS #278-776 or 278-775 and DON'T use their regular hookup
wire if you know what’s good for you and your PRO-34.

NOTE: Don’t ground any of the lugs on the 3/32" Remote
jack to scanner ground. They should be connected only to
the relay pins and nothing else. The ground lug of the
Remote should be wired to one of the relay switch pins
and the lug on the jack farthest from the ground lug will
be wired to the other relay switch pin. The middle lug
of the Remote Jack will not be connected.

Speeding Up Scan and Search in the PRO-34

This is well covered in MOD-38 in Vol-2 of my book, but I
can add a little to it now. The best way to do this mod
is to remove CX-1 , the original stock 2 MHz resonator.
This is done by lifting the Logic/CPU Board up and out of
the front case so you can access the bottom side of the
PCB. Drats, but there’s a shield in right over the
solder points of CX-1 and it will have to be desoldered
in three places to be moved out of the way. A hassle,
but worth the time and effort. Desolder CX-1 and remove
it from the board. For warp drive, install a 7.37 MHz
resonator salvaged from a speeded up PR0-2004 or 2005, or
else order the 7.37 MHz resonator from Tandy National
Parts in Ft. Worth, TX; (800) 442-2425. Ask for part #
CST7.37MT from either the PR0-2004 or 2005. My PRO-34
now races along at something like 33-ch/sec; of course
the delay was reduced to about a half-second, but...!!!
You can always go with something a bit more "reasonable"
like 3 or 4 MHz. Radio Shack’s color burst crystal at
3.58 MHz, #272-1310, has been reported to work well.

=-=- DANGER WITH RADICAL SPEED-UPS IN SCANNERS -=-=

There’s a lot of hype and hyperbole about speeding up the
scan & search rates of scanners these days. There is
also a danger of blowing up the expensive CPU chip if you
get too carried away. Let me explain: CPU’s are little
more than a container for a huge array of electronic
"gates" or doorways. All CPU’s are driven by a clock
oscillator for precise timing or synchronization of those
gate openings and closures. The critical thing here is

"THE WORLD SCANNER REPORT" (c) 1991

VI N5 - Page 5

that every opening or closure requires a bit of current*
When the clock oscillator is increased in frequency, then
there are more gate operations per second, and therefore
a higher current requirement per second. Well, current
flow per second is a basic quantity of power... and one
form of power is heat! And, heat destroys CPUs. So the
faster you run them, the greater the current drain and
there is a point where a failure will occur. Count on
$40, minimum, if you replace the CPU yourself; and $100 &
up if someone else has to do it. I can’t be sure of all
the exact engineering limits of the CPUs in various
scanners, but I am fairly certain that up to 10 MHz is
safe in the PR0-2004 and 2005; 16 MHz for the PR0-2006;
7.37 MHz for the PRO-34; 800 KHz for the Uniden BC-200/
205XLT, and that’s about all on which I can speak with
any certainty. As a rule, SQ% speed ups appear fairly
safe; any more than that without knowing for sure could
lead to problems. I am quite confident that 18 MHz blew
up a CPU in one PR0-2006 that I know of, though I have
successfully used 18 MHz in a number of others. As a
result of this suspicion, however, I will not take a 2006
above 16 MHz anymore. Speeding up scanners is a lot like
revving car engines. Use caution; there are limits!

=-=- SPEEDING UP THE BC-200/205XLT & REGENCY R-4030 -=-=

MQD-41 in Vol-2 of my Scanner Modification Handbook
covers this pretty well, but at the time I didn’t know of
a ready source for speed up resonators unless you were
willing to buy a zillion from Murata-Erie which won’t
sell you just one. Now I know where you can get just one
and maybe a few other neat things besides. See page 2 of
this issue for the address & phone number of Digi-Key
Corp. They have Panasonic EF0-A80DK04B ceramic 800 KHz
resonators for sale at less than a buck each. Digi-Key ’s
part number is P-9947. An 800 KHz resonator will double
the SCAN & SEARCH speeds of the BC-200/205XLT. Digi-Key
also has slower resonators if you’d prefer milder speeds.

By the way, *16% of ”WSR” readers own a BC-200/205XLT.
How do I know? From the data on the subscription blank!

=-=- HOT TIP FOR PR0-2Q04/5/6 & OTHER BASE SCANNERS -=-=

After your base scanner has been operating for a while,
put your hand on the top cover. Notice how warm it is?
If as cool as a cucumber, then go on and find something
else to read in this issue. If the case is any warmer
than the surrounding air temperature, then this article
is for you (and your scanner).

A handheld scanner is great; stick in a battery pack and
off you go; else power it from an AC-DC adaptor. Base
scanners are great too; plug ’em into the wall where they
stay and heat up. Heat accelerates the aging or metabolic
rate of just about everything in the Universe, especially
things electronic or electrical. Cooling or prevention
of heat build-up will prolong the life of most electronic
equipment, and your scanner is a composite example of the

point I will be making here. Inside your scanner is a
bit of practically everything, from crystal to oscillator
to computer to RF and audio amplifier. All these circuits
work best and last longer if operated at reasonably cool
temperatures. Refrigeration not necessary; just rear

Whenever electricity flows in a circuit, a bit of heat is
generated from every device through which current flows.
By and large, we can’t do^ny thing about that. Power (P)
equals Current squared (I ) times resistance (R). So if
two jjilliamps flow through a 1000 ohm resistor, then
.002 x 1000 = .004 watts generated. Not much, but more
or less current flows through lots of circuits with lots
of components in your scanner, and each one releases a
bit of heat into the air inside the case. Cumulatively
this might add up to several watts which even in a closed
space will not cause an inordinate rise in temperature.
So why does the scanner’s case FEEL WARM, even hot? There
is another source of heat that can be under your control!
The transformer in the scanner’s power supply

If your scanner is one like the BC-760/950XLT , then
things are already under control since it does not have
an internal power supply; it runs from an external AC-DC
adaptor or other DC power source. But if you have a
PRD-2004, 2005, 2006, or other base scanner with a cord
that plugs into a 110-v wall socket, then you’ve already
noticed how warm your scanner can get. And you can do
something about that at relatively low cost.

If yours is A/C powered, then all current that circular

in your scanner has to pass through the power transformer
first and that’s where a lot of that current is consumed
and transformed into HEAT! That heat is radiated into
the air space inside the scanner where it raises the
temperature of everything; not just the case that you can
feel! The ’’secret of scanner immortality” is to not use
its internal power supply!

The PR0-2004/5/6 and many other base scanners come with a
DC power jack on the rear panel. This jack has a tiny
switch in it which if the proper plug is inserted, will
disconnect the internal A/C power supply and allow the
scanner to operate from a source of external DC power!
It is highly recommended that YOU power your scanner this
way to minimize the heat accumulation inside the scanner,
and make it run demonstrably cooler! So how to do it?

All you need is a power supply or an AC-DC adaptor that
will provide 10 to 16 volts and rated at about 500-ma
(1/2 amp). Radio Shack has four models that will power
the PR0-2004/5/6 or any of their base scanners: 22-120;

22-127; 273-1653; 273-1652. The first three are a bit
pricey because they’re designed to handle more than just
a scanner, but the last one is priced right and it comes
with the exact plug that you’ll need. Get the polar
of the plug right with center (+) and outer shell (-) and
you’ll be in business. After a while, notice how cool
your scanner runs and then feel the AC-DC adaptor... it

’’THE WORLD SCANNER REPORT” (c) 1991

\I 1N5 - Page 6

will be warm... and that heat will not be accumulating
inside the scanner!!!

Some of you more technical types might suggest that a
regulated power supply is best from which to operate the
-2004/5/6 or other base scanner. Really, it doesn’t
matter, though if you already have one available, then by
all means, use it. The thing is that the built-in power
supply in the PR0-2004/5/6 is cheap, rated at 12-v/5G0-ma
which then feeds several regulator circuits. It’s no
different if you use an external supply, which will also
feed the internal regulator circuits. So you can drive
your PR0-2004/5/6 with most anything between 10-16 vDC so
long as it can produce upwards of a half -amp (500-ma) or
so. There is only one circuit in the PR0-2004/5/6 which
operates on an unregulated voltage, and that is the audio
power amplifier chip, IC-7, which runs straight off the
12-v supply line. IC-7 is capable of operation over a
rather wide range of at least 3 to 16 volts, so it is not
critical at all. USE AN EXTERNAL DC POUER SOURCE FOR YOUR
SCANNER TO MAKE IT RUN COOLER AND PRESERVE ITS LIFE.

What If Your Base Scanner Doesn't Have A DC Jack?

Why not install one? Chances are that the mfgr left it
out to save a buck. Most modern scanners can be readily
converted to work with external 12-vDC if they don’t
already come that way. You 1 11 need a drill, a bit of
wire and a jack of choice. An RCA Phone jack will be just
fine and is easy to install and connect. You can also
a standard coaxial power jack such as Radio Shack ? s If
,-1563 or similar. I 1 11 leave that up to you. The
main thing you need to know is about the wiring of the
jack. Its shell or the part that contacts the scanner’s
metal chassis will be (-) while the center or hot lug
will be (+)• Now you know the hard part.

Chances are that the scanner has an internal 12-v power
supply which is hard-wired to the 110 VAC cable. The low
voltage DC output of the internal power supply will run

'THE HOIILD SCANNER REPORT * (c)

pretty much straight to the ON-OFF Switch, and that’s
where you’ll want to pay attention with a voltmeter.
Connect the (-) lead of the voltmeter to the scanner’s
metal chassis or a PCB ground trace. Use the (+) lead of
the meter to measure as described below. One side of the
On-Off switch will have full time +12v, give or take a
couple of volts regardless of whether or not the switch
is ON. (+10 to +16 vDC will be fine.) Now the other side
of the switch is where you’ll verify with the voltmeter
that is turned ON or OFF with the switch. When you find
that spot, solder a wire to the unswitched lug. Solder
the other end of that wire to the center or hot lug of
the new power jack discussed above. Bingo! You’re done!
Now your scanner can go mobile if you like or it can be
operated on the base (much cooler) with an external AC-DC
Adaptor as discussed in the preceding section of this
article. A word of caution: don’t leave the A/C cord
plugged into the wall if you’re using external DC power.
Your new DC Power Plug probably won’t be switched like
that discussed for the PR0-2Q04, 2005 & 2006.

NOTE: It is possible, though not probable, that some base
scanners will use an internal power supply radically
different from 12-volts. If yours is such, sorry this
article isn’t for you. That’s why you need to make a
couple of basic checks with a voltmeter first. If the
switched voltage that you encounter is between 10 and 16
volts, then you’re in good shape; a 12-v external AC-DC
Adaptor or automotive 12-volts will power your scanner.

=-=- MORE DIFFERENCES AMONG THE PRQ-2004/5/6 -=-=

Ever since the PR0-2005 came out and then the 2006, I
have been saying that they’re all the same radio. Well,
they are, but there are small differences from one to the
next. Last issue, we showed you how to implement the
PR0-2006 ’s nifty Squelch Hysteresis switch into your
PRQ-2004, 2005 and maybe other scanners. We all know
about the different CPU in each of the three, and how the
2006 ’s runs much faster than the 2004/5. There are two

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other differences that I want to tell you about now*

First, did you know there are two different versions of
the PR0-2004 ’s CPU? Early models came with a CPU marked
GR-327 while later ones are GR-0327A. The earlier 327 is
programmed to switch the 30-KHz Step increment on for the
old Cellular Phone bands of 825-845 MHz and 870-890 MHz.
The later 0327A CPU kicks in the 30 KHz Step for the most
recent cellular bands; 824-849 MHz and 869-894 MHz. To
find out which you have, program your 2004 for a LIMIT
SEARCH of 869-894 MHz. If the 30 KHz flag remains on
throughout either of those bands then yours is the 0327A,
but if "12.5 KHz" comes on in the 869-870 and 890-894
ranges, then yours is the 0327. Of course, you can
always pop the case and look at your CPU. It’s marked on
the body of the chip. If you have the older chip, you
can acquire the newer 0327A from Tandy and install it
yourself. 30 KHz steps for the newer CMT sub-bands is
the only advantage of the 0327A that I have been able to
determine. The CPUs in the PR0-2005 and PR0-2Q06 already
have this update so it’s a factor only in PR0-2004 ’s.

Now here is another difference between the PR0-2005/6 and
the PR0-2004. I’ve known about it for some time but have
forgotten to mention it. There are two extra IF filters
in the PR0-2005/6 that are not in the PR0-2004. One of
these is a second 10.7 MHz ceramic IF filter for the lilFM
section and the other is a narrower 455 KHz ceramic IF
filter for the AM section! I don’t see a great advantage
of the extra 10.7 MHz lilFM filter in the PR0-2005/6 but it
must improve selectivity and spurious rejection somewhat.
But the addition of the narrow 455 KHz filter in the AM
section is a definite plus of the PR0-2QQ5/6 over the
PR0-2004 which has none there. Here’s how you can tell
the difference. Program your PR0-2004/5/6 ’s with some CB
channels or do a LIMIT SEARCH of 26.96 MHz to 27.41 MHz.
When you hear fairly strong signals, stop and check the
adjacent channels of + and - 10 KHz from the one where
the signal seems the strongest. In the PR0-2004, chances
are that you will be able to hear the same signal equally

well on two or more channels. Here’s an example: say a
signal is on 27.025 MHz (CB Ch-6). If you can clearly
hear that same signal on 27.015 and/or 27.035 MHz, then
yours is a PR0-2Q04! PR0-2005/6 f s won’t hear that signal

at all or if so, it won’t be as clear. This is due i
the extra selectivity offered by CF-3 in the PR0-200^
lile will offer a nice and easy update mod for PR0-2004 ’s
and an enhancement for more improvement of PR0-2005/6 ’s
in a coming issue so stay tuned.

Now here is the tech issue. All PR0-2004/5/6 scanners
have the same IF filter for NFM, and it’s bandwidth is
about 15 KHz, rather wide, but necessary for sloppy NFM
stations out there on VHF & UHF. In the PR0-2004, the
output of this filter feeds both the NFM and AM s.ections
and is the sole determinant of selectivity. In the
PR0-2005/6, the output of this filter feeds the NFM
section the same as the PR0-2004, but it also feeds a
narrower 6 KHz wide filter (CF-3) at the head of the AM
section. This extra filter makes the AM section more
selective than the NFM which is righteous and proper! In
the PR0-2004, the selectivity of the AM and NFM sections
are about the same, which is not so good when it comes to
trying to separate the congested CB and Freeband channels
between 25-28 MHz. It might also be a problem on the VHF
Aero band in crowded flight areas. Good selectivity has
always been an elusive goal since radio was invented!

Now the thing is that you might not ever have noticed the
deficient selectivity of the AM section in the PR0-2nn4
because most of your operations may be in the V HF
bands where NFM is the common mode and where regulatory
frequency coordination helps minimize adjacent channel
congestion. Selectivity might not ever have been an issue
for you, but if you’re a CB’er or compleat scannist, then
you may have been concerned and this eye-opener can prove
fruitful later. I have been improving the selectivity of
receivers of all types and kinds for many years and we
will concentrate on this area in the issues ahead, not
only for the PR0-2004/5/6 but for most scanners as well!

'THE HDHLD SCMEf ! REPORT' (cl 1991 VMS - Page 8

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"THE WORLD SCANNER REPORT**
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TURBO-WHOPPER PR0-2006! Shown are the LED Center Tune Meter;
LED S-Meter; Keyboard Memory Block Controller LEDs, 4-seqDIP
Switch for misc switch needs; Extended Delay adjust and LED
Indicator for the Extended Delay. Not shown are many more!

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